Las Vegas, NV, USA
N567EM
DASSAULT AVIATION MIRAGE F-1
A fighter jet airplane providing combat training support to the Department of Defense collided with terrain shortly after entering the final turn in the traffic pattern. The pilot was returning to the airport after completion of tactical area work. As the airplane began the final turn (a 180° turn to align with the runway), its airspeed was about 170 kts and slowing. Shortly after, the pilot reported that he was having a flap issue and the airplane’s descent rate increased from 1,000 fpm to more than 3,000 fpm. The airplane’s airspeed dropped to below the listed low-speed limitation without flaps (160 kts) for about the final 14 seconds of flight. The flight manual advises pilots to land at a speed between 195 and 215 kts if the flaps do not lower. At the last recorded data point, the airspeed was 135 kts and slowing. Shortly thereafter, the pilot initiated an ejection. The airplane subsequently struck terrain in a residential area and was consumed by a postimpact fire. Postaccident examination of the airplane revealed that the flaps were likely not extended. During the preflight check of the slats and flaps, the leading-edge slats operated appropriately but the flaps did not initially extend during the first cycle of the check. The pilot was able to correct the issue and completed at least two additional cycles during the operational checks of the slats and flaps with no further issue. Whether this flap issue was a reoccurrence of the ground check anomaly, or another cause could not be determined due to the post-crash condition of the airplane and the absence of onboard recorded data. Postaccident analysis of the bulb filament revealed that the airplane’s master failure warning light was showing an amber light indication. Which annunciator caused the amber light to illuminate could not be determined but an amber light indication allowed for delayed action for the issue. If a red light was illuminated, it would call for immediate action. No additional evidence of preimpact mechanical malfunctions or failures that would have precluded normal operation of the airplane were observed. Failure of the flaps to extend would require additional speed to compensate for the loss of lift, which would increase the airplane’s turning radius. Because the traffic pattern’s normal ground track is based on the airplane being configured with the flaps extended, a no-flap configuration would require the airplane to increase bank and angle of attack (AOA) to maintain the track. However, insufficient thrust was available to overcome the configuration issue and increased AOA. Under a failed flap scenario, the pilot would have needed to maintain adequate airspeed, AOA, and rolled out of bank and discontinued the final turn for an airplane configured with the flaps extended and then flown a traffic pattern ground track consistent with a no-flap configuration. The pilot likely maintained his ground track during the final turn in order to reduce the chance of conflict with potential landing traffic on the opposite runway if he rolled out of bank and pattern/airspace restrictions. It is likely that the pilot initiated an ejection outside of the airplane’s ejection seat minimum altitude ejection envelop due to the airplane’s increased bank, decreased airspeed, low altitude, and sink rate.
HISTORY OF FLIGHTOn May 24, 2021, about 1417 Pacific daylight time, an experimental Dassault Aviation Mirage F-1 Turbo-jet, N567EM, was destroyed when it was involved in an accident near Nellis Air Force Base, (LSV), Las Vegas, Nevada. The pilot was fatally injured. The airplane was operated by Draken International as a public-use aircraft in support of the United States Air Force’s simulated combat training. The accident airplane was the No.1 (lead) airplane in a flight of 2 airplanes that were returning to LSV after completion of their Weapons School support flights in the Nevada Test and Tactics Range. The No. 2 airplane in the formation returned to LSV before the lead airplane since it reached its briefed fuel status first. About 15 minutes later, the lead airplane returned to LSV. While en route to LSV and about several minutes out, the lead pilot reported that the airplane was “code 1,” signifying that the airplane had no maintenance discrepancies. A review of LSV airport surveillance radar and air traffic control communications revealed that the lead airplane entered the traffic pattern and reported initial for runway 3R at 14:16:05. At 14:16:26, the airplane was aligned with runway 3R, flying about 2,000 ft above ground level (agl) and at an airspeed of about 260 kts. The airplane broke right for the overhead pattern and while on downwind and approaching the final turn (a 180° turn towards the landing runway), at 14:17:12, the pilot reported that he would be accomplishing a low approach and then proceeding out to Flex (LSV 338/04). As the airplane began the final turn it was about 1,400 ft agl, and the airspeed was 170 kts and slowing. Shortly after, the airplane’s descent rate increased from 1,000 fpm to more than 3,000 fpm. At 14:17:20, the airplane’s airspeed decreased below 160 kts, and the pilot reported “we are having a ugh flap issue” and the tower responded, “are you declaring an emergency” to which the pilot responded “affirm.” At 14:17:36 the last recorded point, about 400 ft agl, the airplane’s airspeed was 135 kts and slowing. The airplane’s airspeed was slower than the listed low-speed limitation, without flaps (160 kts), for about the final 14 seconds of flight. Furthermore, the airplane continued to slow to below the low-speed limitation for the flaps extended. The flight manual advises that if the flaps do not lower, to land at a speed between 195 and 215 kts. The airplane continued to descend in the final turn in a bank angle in excess of 40°. The pilot ejected from the airplane but was fatally injured. Shortly thereafter, the airplane struck terrain in a residential area southwest of the approach end of the runway. The wreckage was consumed by a post-crash fire. Ground personnel stated that during the preflight check of the slats and flaps the leading-edge slats operated appropriately but the flaps did not initially extend during the first cycle of the check. The pilot was able to correct the issue and completed at least two additional cycles during the operational checks of the slats and flaps with no further issue. PERSONNEL INFORMATIONThe pilot held a commercial pilot certificate with an airplane single-engine and multi-engine land and airplane instrument ratings. He also held an experimental aircraft authorization for the DA-F1. The pilot was issued a Federal Aviation Administration (FAA) second-class medical certificate on January 19, 2021, without limitations. The pilot logged 2,859 total hours of flight experience and 152 hours in the F-1 aircraft. He was a former fighter pilot in the United States Air Force. The pilot had completed training provided by the company and was qualified in the F-1 airplane for the mission flown. The pilot appeared to be in good spirits and rested on the day of the accident and on the previous workday. AIRCRAFT INFORMATIONThe F-1 Mirage was a French fighter and attack aircraft that was imported into the United States and registered under the experimental category. It is a single-engine, swept-wing, supersonic airplane capable of Mach 2+. The airplane had a maximum takeoff weight of over 35,000 lbs. The airplane is equipped with high-lift devices consisting of two types of leading-edge slats and double-slotted flaps on each wing. The internal drooping slats occupy the 2/5 of the leading edge and have a camber of 25°. The external slotted slats occupy 3/5 of the leading edge, are in line with the drooping slats, and have a variable camber. The flaps have slots and slips in two parts (internal and external). Their camber is different and variable depending on the configuration. In the 1/2 extended position, the internal flap is about 28° and the external flap is 13°. In the fully extended position, the internal flap is about 48° and the external flap is 25°. The airplane’s manual control of the high-lift devices was controlled electronically by the “SLATS-FLAPS” lever. This control level must be used on takeoff and landing and overrides the combat high-lift device controls. There were three positions of the handle: the forward position was fully retracted and guarded by a guard cover, the middle position was ½ flaps and slats completely extended. The rear position was flaps and slats completely extended. The slat control system and the two flap actuating jacks were supplied by the hydraulic system 1, ancillary subsystem. The airplane’s high-lift device selector switch had an EMERGENCY RETRACTION position for slat and flap emergency retraction. This position would take precedence over all other current functions selected. The combat flaps were for use during combat and increase the lift performance by 25% up to about 18° nose up. The F-1 Aircraft Flight Manual for “Landing High-Lift Devices Fail to Extend” checklist calls to check the Slats/Flaps (S/F) circuit breaker, utility hydraulic pressure, and that the high-lift device selector switch in not at EMERGENCY RETRACT position; S/F light out. If the checks confirm the failure, set the slat/flap lever to IN and land without high-lift devices: angle-of-attack (AOA) incidence about 11°. The no-flap landing speeds were incorporated in the hydraulic system ancillary shutoff emergency checklist. The checklist states that if the high-lift devices (slats and flaps) do not extend, land with and airspeed between 195 kts to 215 kts depending on aircraft weight and also with an AOA incidence about 11° as per the “Landing High-Lift Devices Fail to Extend” checklist. Given the accident airplane was at landing weight, its no-flap landing speed would have been about 195 kts, which assumes the airplane was straight and level and configured with the gear extended. Additionally, Draken International’s F-1 procedures call for no-flap patterns to be flown from a straight in approach. The aircraft flight manual for the normal F-1 “Break” pattern depicts initiating the break to downwind about 350 kts, 60° of bank, throttle back to below 6,500 rpm and airbrakes as required. Abeam the runway, the airplane should be about 215 kts, configured with the airbrakes in, gear down, and flaps down. The pilot should, according to the manual, extend the downwind leg sufficiently to stabilize speed before the final turn. Approaching the runway at 45°, the key point for the final turn, airspeed should be about 160 kts and AOA incidence about 10°, and RPM about 7,300 rpm. During the final turn, airspeed should be about 150 kts and the pilot should use the AOA incidence indicator to control airspeed, less or equal to 13° (12° - 13° on average). Draken International flies their normally configured F-1s in the overhead pattern at a minimum of 165 kts in the final turn. Additionally, an incidence of 13°AOA is used only after touchdown and aerobraking, which would equal about 135 kts (assuming about a 1000L of fuel landing weight). The airplane’s incidence indicator is attached to the left side windshield post and displays incidence (AOA) information. At a greater than 17° limit incidence, a warning horn activates, and cuts off when the incidence is reduced to 14°. The maximum permissible incidence (AOA) is 17°. According to the airplane’s flight manual: The aircraft behavior at high incidence is very sound. The permissible limit is easily exceeded unless the incidence indicator is watched, the control forces on the control stick are very light and the buffeting level is low and constant. The control stick is often pulled up to the pitch travel limit without any obvious anomaly, especially with the combat flaps. The airplane was scheduled on an Other Approved Inspection Program (AAIP). The program consisted of three levels of progressive aircraft inspections. The maintenance and inspection levels were organizational, intermediate, and depot. Organizational inspections consisted of servicing, preventive maintenance, and operational inspections. Intermediate level inspections consisted of intermediate inspections at an interval of 250 flight hours and a minor inspection at 800 flight hours. The depot inspections consisted of a major inspection at 2,400 flight hours. The operator performed a daily inspection on the accident airplane prior to its flight. Additionally, the airplane’s last intermediate and depot level inspections were accomplished on November 9, 2020, at an airframe total time of 4,589.7 hours. AIRPORT INFORMATIONThe F-1 Mirage was a French fighter and attack aircraft that was imported into the United States and registered under the experimental category. It is a single-engine, swept-wing, supersonic airplane capable of Mach 2+. The airplane had a maximum takeoff weight of over 35,000 lbs. The airplane is equipped with high-lift devices consisting of two types of leading-edge slats and double-slotted flaps on each wing. The internal drooping slats occupy the 2/5 of the leading edge and have a camber of 25°. The external slotted slats occupy 3/5 of the leading edge, are in line with the drooping slats, and have a variable camber. The flaps have slots and slips in two parts (internal and external). Their camber is different and variable depending on the configuration. In the 1/2 extended position, the internal flap is about 28° and the external flap is 13°. In the fully extended position, the internal flap is about 48° and the external flap is 25°. The airplane’s manual control of the high-lift devices was controlled electronically by the “SLATS-FLAPS” lever. This control level must be used on takeoff and landing and overrides the combat high-lift device controls. There were three positions of the handle: the forward position was fully retracted and guarded by a guard cover, the middle position was ½ flaps and slats completely extended. The rear position was flaps and slats completely extended. The slat control system and the two flap actuating jacks were supplied by the hydraulic system 1, ancillary subsystem. The airplane’s high-lift device selector switch had an EMERGENCY RETRACTION position for slat and flap emergency retraction. This position would take precedence over all other current functions selected. The combat flaps were for use during combat and increase the lift performance by 25% up to about 18° nose up. The F-1 Aircraft Flight Manual for “Landing High-Lift Devices Fail to Extend” checklist calls to check the Slats/Flaps (S/F) circuit breaker, utility hydraulic pressure, and that the high-lift device selector switch in not at EMERGENCY RETRACT position; S/F light out. If the checks confirm the failure, set the slat/flap lever to IN and land without high-lift devices: angle-of-attack (AOA) incidence about 11°. The no-flap landing speeds were incorporated in the hydraulic system ancillary shutoff emergency checklist. The checklist states that if the high-lift devices (slats and flaps) do not extend, land with and airspeed between 195 kts to 215 kts depending on aircraft weight and also with an AOA incidence about 11° as per the “Landing High-Lift Devices Fail to Extend” checklist. Given the accident airplane was at landing weight, its no-flap landing speed would have been about 195 kts, which assumes the airplane was straight and level and configured with the gear extended. Additionally, Draken International’s F-1 procedures call for no-flap patterns to be flown from a straight in approach. The aircraft flight manual for the normal F-1 “Break” pattern depicts initiating the break to downwind about 350 kts, 60° of bank, throttle back to below 6,500 rpm and airbrakes as required. Abeam the runway, the airplane should be about 215 kts, configured with the airbrakes in, gear down, and flaps down. The pilot should, according to the manual, extend the downwind leg sufficiently to stabilize speed before the final turn. Approaching the runway at 45°, the key point for the final turn, airspeed should be about 160 kts and AOA incidence about 10°, and RPM about 7,300 rpm. During the final turn, airspeed should be about 150 kts and the pilot should use the AOA incidence indicator to control airspeed, less or equal to 13° (12° - 13° on average). Draken International flies their normally configured F-1s in the overhead pattern at a minimum of 165 kts in the final turn. Additionally, an incidence of 13°AOA is used only after touchdown and aerobraking, which would equal about 135 kts (assuming about a 1000L of fuel landing weight). The airplane’s incidence indicator is attached to the left side windshield post and displays incidence (AOA) information. At a greater than 17° limit incidence, a warning horn activates, and cuts off when the incidence is reduced to 14°. The maximum permissible incidence (AOA) is 17°. According to the airplane’s flight manual: The aircraft behavior at high incidence is very sound. The permissible limit is easily exceeded unless the incidence indicator is watched, the control forces on the control stick are very light and the buffeting level is low and constant. The control stick is often pulled up to the pitch travel limit without any obvious anomaly, especially with the combat flaps. The airplane was scheduled on an Other Approved Inspection Program (AAIP). The program consisted of three levels of progressive aircraft inspections. The maintenance and inspection levels were organizational, intermediate, and depot. Organizational inspections consisted of servicing, preventive maintenance, and operational inspections. Intermediate level inspections consisted of intermediate inspections at an interval of 250 flight hours and a minor inspection at 800 flight hours. The depot inspections consisted of a major inspection at 2,400 flight hours. The operator performed a daily inspection on the accident airplane prior to its flight. Additionally, the airplane’s last intermediate and depot level inspections were accomplished on November 9, 2020, at an airframe total time of 4,589.7 hours. WRECKAGE AND IMPACT INFORMATIONExamination of the accident site revealed that the jet airplane impacted flat desert terrain in the back of a residence about 1.5 miles southwest from the approach threshold of runway 3R. All major components of the airplane were found at the main wreckage site. The main portion of the fuselage came to rest by a flatbed semi-truck trailer on a heading of about 195° magnetic. Small fragments of aircraft debris were scattered several hundred feet from the accident site. The wreckage site was at an elevation of about 1,791 ft msl. There was a postimpact fire that consumed the majority of the airplane wreckage. The ejection seat and parachute were found about one block away to the east-southeast. A postaccident examination of the airplane wreckage revealed that the airplane’s configuration was consistent with the slats being extended and the flaps being retracted. Observation of the airplane’s engine revealed significant impact damage consistent with the engine operating at a high rotational velocity at the time of impact and that there was no evidence of internal catastrophic damage. The engine rpm gauge as found indicated about 7,100 rpm, which was consistent with “break” pattern procedures for a normally configured aircraft. Additionally, the position of th
The pilot’s exceedance of the airplane’s critical angle of attack on approach and failure to fly a traffic pattern track consistent with a no-flap configuration. Contributing to the accident was the failure of the airplane’s flaps to extend while in the traffic pattern for an undetermined reason.
Source: NTSB Aviation Accident Database
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